Evaluating ion dynamics through Coulomb and Yukawa interaction potentials in one component strongly coupled plasmas

TL;DR

This study uses molecular dynamics simulations to compare ion dynamics in strongly coupled plasmas with Coulomb and Yukawa potentials, revealing how electron screening influences heating, diffusion, and stability.

Contribution

It provides new insights into the effects of electron screening on ion behavior and energetics in strongly coupled plasmas using Coulomb and Yukawa models.

Findings

Electron screening in Yukawa potential limits disorder-induced heating.

Ions exhibit sub-diffusive behavior during non-equilibrium phase with Coulomb potential.

Yukawa potential results in lower potential energy, enhancing system stability.

Abstract

Atmospheric pressure helium plasmas are investigated through molecular dynamics simulations at room temperature (300 K) for various ionization fractions ($\chi_i = 10^{-1} - 10^{-5}$) in the strongly coupled regime (ion coupling parameter, $\Gamma_i \sim 1 - 10$) employing Coulomb and Yukawa interaction potentials. The role of electron screening in ion dynamics and energetics is examined through ion and gas temperatures, mean squared displacement of ions, ion coupling parameter, and radial distribution function of the system. It is found that electron screening in the Yukawa potential significantly limits the disorder-induced heating (DIH) mechanism for strongly ionized plasmas ($\chi_i$ $\ge 10^{-3}$). Whereas, ions show a prominent sub-diffusive behavior associated with the DIH during the non-equilibrium phase for the Coulomb potential. The DIH mechanism is explained using a model based upon the conservation of energy. However, for weakly ionized plasmas ($\chi_i \le 10^{-4}$), the maximum ion temperatures are almost similar for both potentials. Furthermore, electron screening affects the separation distance and arrangement of the ion-neutral pairs for all the values of $\chi_i$. In general, Yukawa potential results in a lower mean potential energy of the interacting particles, which is energetically favourable for the stability of the system.